It is known to equip a road vehicle with a collision detection system designed to detect a potential collision with another vehicle or other object, and to avoid the collision by taking corrective action, for example by applying the brakes. Such a system may use one or more sensors to detect the proximity and relative motion of an object with which the vehicle may collide. Typical sensors that may be used for this purpose include radar, capacitive sensors, laser sensing, and acoustic sensing, which may be used with sensors for determining the kinematics of the vehicle, such as accelerometers. Such sensors detect an object within a pre-defined field of view, typically with a forward-facing field of view. Capacitive sensors known for this purpose have two or more electrodes mounted on the vehicle, and detect the proximity of objects in front of the electrodes by a change in mutual capacitance between the electrodes, caused by the effect of the object on the electrical field between the electrodes. Typically, separate arrays of transmit and receive electrodes may be used to give a defined forward-facing detection zone. Because such systems are designed primarily to avoid collisions, they are not omni-directional, so that they may not detect side or rear collisions without the deployment of additional sensors. Vehicles may have systems to detect major collisions, such as systems to deploy airbags in a crash. However, existing systems for collision avoidance have limited capability for collision diagnosis, for example in detecting whether a collision, and for example a small scale impact, has actually occurred, and in particular existing systems lack omni-directional detection of a collision.
It is an object of the invention to address at least some of the limitations of the prior art systems.